15C-6 |
The effect of carrageenan on quality of fermented lactic beverages |
A. L. B. PENNA, Departamento de Engenharia e Tecnologia de Alimentos, UNESP, Cristóvão Colombo, 2265, São José do Rio Preto - SP, 15054-000, Brazil, F. L. Hoffmann, and M. N. Oliveira, Departamento de Tecnologia Bioquímico-Farmacêutica, USP, Prof. Lineu Prestes, 580 B-16, São Paulo - SP, 05508-900, Brazil. Fermented lactic beverages occupy a very satisfactory position in the dairy products market and a tendency of a consumption increase in next few years is very strong. The reason for using carrageenan in dairy products is because it improves product texture, provides body and stability to liquid formulations. The objective of this study was to determine the effect of carrageenan on physicochemical, sensory and rheological characteristics of fermented lactic beverages. Fermented lactic beverage evaluation (pH, fat, total solids, appearance, consistency and taste) was done to verify the quality of the product. Response surface methodology was used to establish adequate relationship of independent variables (gum concentration and total solids content of yogurt/whey mixture) with dependent variables (consistency index and flow behavior index). Rheological measurements were done using a cone and plate rheometer. The flow curves were described by the power law and Herschel-Bulkley models. The ANOVA of the results were conducted from incomplete block design, using Tukey test. The pH value varied from 4.02 to 4.66, fat varied from 0.20 to 1.43 % and total solids content from 15.25 to 17.96 %, characteristics of normal products. The sensorial evaluation showed that the higher the concentration of carrageenan and the lower amount of whey used in the formula, the most acceptable the product was. In all analysed conditions, all samples presented a non-Newtonian behavior. The shape of flow curves indicates a shear thinning (thixotropic) nature of the samples. The highest area enclosed between up- and down-curves (hysteresis loop) was obtained when the highest concentration of carrageenan was used. Fermented lactic beverages manufactured with yogurt and whey, under experimental conditions, showed suitable rheological characteristics, and good acceptability. So, the correct choice of type of gum and gum concentration and also appropriate total solids content of the mixture leads to a feasible technology process.
Session 15C, Dairy Foods
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